1. Field of the Invention
This invention relates to novel Fredericamycin A derivatives.
2. Description of the Prior Art
It has hitherto been known that an antitumor antibiotic represented by the following formula (II): ##STR4## Fredericamycin A (NSC-305263) can be isolated from a culture of Streptomyces griseus FCRC-48 ["J. Antibiotics", 34, 1389-1401(1981); ibid, 34, 1402-1407(1981)].
Fredericamycin A is however accompanied by such problems that its antibacterial activities are weak and its stability is low.